edits are not applied on the imported .mp4 media

Hii opend camtasio studio 9 and from file menu / import / media , i imported a .mp4 media (which was created via this same camtasia studio)i added media to timeline and i started doing some edits on it (for example removing some area of that clip) and then i hit ctrl + s to save and also at the media bin, i righ click on that .mp4 media and selected update media.but when i play that .mp4 media, my changes are not take effect. seems changes are not saved on that media.

You are working with a non-destructive editor; your changes to the clip only exist in the timeline editor and your original media is unchanged. You must RENDER the timeline project to a new clip; this will reflect the changes you made.